Hydrorefining of crude oil and catalyst therefor



sene, light gas oil, etc.

United States Patent Delaware No Drawing. Filed Dec. 20, .1961, Ser. No. 169,952.31 8 Claims. (Cl. 208-264) The present invention relates to a novel method for preparing a catalyst especially adaptable for utilization in the hydrorefining of petroleum crude oils, heavy vacuum gas oils, heavy cycle stocks, etc. More specifically, the

' present invention involves a process for the hydrorefining of heavy hydrocarbon charge stocks to eliect the removal of nitrogen and sulfur therefrom, and afiords unexpected advantages when employed for the removal of metals and/or to convert the pentane-insoluble fraction thereof into pentane-soluble hydrocarbon oils.

Crude petroleum oil, and the heavier hydrocarbon fractions and/ or distillates derived therefrom, generally contain nitroge nous and sulfurous compounds in large quantities. In addition, crude oil and heavy hydrocarbon fractions contain quantities of metallic contaminants which exert detrimental effects upon the catalyst utilized in various processes to which the crude oil 'or heavy hydrocarbon fraction is ultimately subjected. The most common metallic contaminants arenickel and vanadium, although other metals including iron, copper, etc., are often present. These metals may occur in a variety of forms: they rnay exist as metal oxides or sulfides, introduced into the crude oil as metallic scale or particles; they may be present in the form of soluble salts of such metals; usually, however, they exist in the form of organo-metallic compounds, such as metal porphyrins and the various derivatives thereof.

Although the metallic contaminants existing as oxide or sulfide scale may be removed, at least in part, by a relatively simple filtering technique, and the water-soluble salts are at least in part removable by washing and subsequent dehydration, a much more severe treatment is required to remove the organo-metallic compounds such as metal porphyrins, and to the extent that the resulting crude oil or heavy hydrocarbon charge is suitable for further, subsequent processing. In addition to organometallic compounds, crude oils contain greater quantities of sulfurous and nitrogenous compounds than are found in lighter hydrocarbon fractions such as gasoline, kero- For example, a Wyoming sour crude, having a gravity of 23.2 API at 60 F., contains about 2.8% by Weight of sulfur'and about 2700 ppm. of total nitrogen. The nitrogenous and sulfurous compounds are converted, upon being subjected to a treating process,

'into hydrocarbons, ammonia and hydrogen sulfide, the

latter being readily removed from the system in a gaseous phase. Reduction in' the concentration of the organometallic compounds is not as easily achieved, and to the exetnt that the crude oil or heavy hydrocarbon charge stock becomes suitable for further processing. Notwithstanding that the concentration of these organo-metallic compounds is relatively small, for example, often less than about 10 p.p.m., calculated as the elemental metal,

subsequent processing techniques will be adversely afiFected the nature of the charge stock being processed and to the desired product quality and quantity, is changed considerably as a result of the deposition of the metallic contaminants onto the catalyst; the changed composite inherently results in changed catalytic characteristics. Such an effect is undesirable with respect to the cracking process, since the deposition of metallic contaminants upon the catalyst tends to result in a lesser quantity of valuable liquid product, and large amounts of hydrogen and coke, the latter producing relatively rapid catalyst deactivation. The presence of organic-metal compounds, including metal porphyrins, affects deleteriously other processes including catalytic reforming, isomerization, hydrodealkylation, etc.

In addition to the foregoing described contaminating influences, crude oils and other heavier hydrocarbon fractions generally contain large quantities of pentane-insoluble material. For example, the Wyoming sour crude consists of about 8.37% by weight of pentane-insoluble asphaltenes which are hydrocarbonaceous compounds considered as coke-precursors having the tendency to become immediately deposited within the reaction zone and onto the catalytic composite employed in the form of a gummy hydrocarbonaceous residue. This constitutes a large loss of charge stock, and it is, therefore, economically desirable to convert such asphaltenes into useful hydrocarbon oil fractions.

The object of the present invention is to provide a process for hydrorefining heavier hydrocarbonaceous material, and particularly petroleum crude oils, utilizing a catalyst prepared in a particular manner. In other processes, the metals contained within the crude oil are removed from the charge stock through deposition of the same on the catalyst employed. This practice greatly increases the amount of catalyst in a very short time, and precludes the use of the fixed-bed catalyst system commonly employed in present-day refining operations. Slurry processes, employing catalytically active metals deposited upon silica and/ or alumina, are very erosive, and make plant upkeep difficult and expensive. The present invention teaches the preparation of a colloidally dispersed, unsupported catalyst useful in a slurry process, and which catalyst Will not effect extensive erosion of the reaction system. The present process yields a liquid hydrocarbon product which is more suitable for further processing without experiencing the difiiculties otherwise resulting from the presence of the foregoing described contaminants. The process of the present invention is particularly advantageous in effecting the removal of organic metal compounds without significant product yield loss, while simultaneously converting pentane-insoluble material into pentane-soluble liquid hydrocarbons.

In a broad embodiment, the present invention relates to a hydrorefining catalyst which comprises at least one decomposed beta-diketone complex of the metals of Group VIB, having an atomic number greater than 24, and the Iron-group.

In another broad embodiment, the present invention encompasses a method of preparing a hydrorefining catalyst which comprises forming a hydrocarbon solution of at least one beta-diketone complex of the metals from Group VI-B, having an atomic number greater than 24, and the Iron-group, and heating said solution at a temperature less than about 310 C. for a time sufiicient to decompose said beta-diketone complex.

The present invention involves a process for hydrorefining a hydrocarbon charge stock, which process comprises admixing said charge stock with at least one betadiketone complex of the metals of Group ViB, having an atomic number greater than 24, and the Iron-group, heating the resulting mixture at a temperature less than about 310 C. and for a time sufiicient to decompose 3 said beta-diketone complex, reacting the resulting colloidal suspension with hydrogen at a temperature in excess of about 225 C. and at a pressure greater than about 500 pounds per square inch gauge, and recovering a hydrorefined liquid product.

More specifically, the present invention aifords a process for hydrorefining a petroleum crude oil containing pentane-insoluble asphaltenes which comprises admixing said crude oil with molybdyl acetylacetonate, heating the resulting mixture at a temperature less than about 310 C. in a non-reducing atmosphere and for a time sufiicient to decompose said molybdyl acetylacetonate, reacting the resulting colloidal suspension with hydrogen in the substantial absence of carbon monoxide, at a temperature within the range of from about 225 C. to about 500 C. and at a pressure of from about 500 to about 5000 pounds per square inch gauge, and recovering said crude oil substantially free from pentane-insoluble asphaltenes.

From the foregoing embodiments, it is readily ascertained that the method of the present invention involves the preparation of a catalyst utilizing metals selected from Group VIB and the Iron-group of the Periodic Table. The catalyst, prepared in accordance with the method of the present invention, may comprise one or more metals from the group of molybdenum, tungsten, iron, nickel and cobalt. It is noted that the metals selected from Group VI-B, namely molybdenum and/ or tungsten, have an atomic number greater than 24. Chromium acetylacetonate, and other beta-diketones of chromium, decomposes at temperatures greater than 310 C., the maximum temperature utilized in the present invention. Other betadiketone complexes decompose at lower temperatures to yield a sulficiently finely-divided slurry. The catalyst is prepared by initially dissolving a beta-diketone complex of the selected metal, or metals, in the hydrocarbon charge stock containing the pentane-insoluble asphaltenes and other contaminating influences, which are to be converted into soluble hydrocarbons. The quantity of the betadiketone complex employed is such that the colloidal suspension, or dispersion, resulting when the complex is decomposed Within the hydrocarbon charge stock, comprises from about 1.0% to about 10.0% by weight, calculated as the elemental metal. compounds include nickel acetylacetonate, molybdyl acetylacetonate, tungsten acetylacetonate, the molybdenum complex of 4,6-nonanedione, mixtures of two or more, etc. These compounds and other suitable betadiketones may be represented by the following structural formula.

In the above structural formula, Me denotes a metal selected from the group of molybdenum, tungsten, iron, nickel and/or cobalt; R and R may be hydrogen, a methyl group, an ethyl group, or other alkyl group containing up to about carbon atoms; R and R" may also be an aryl group, or an alkyl-substituted aryl group, and R" may or may not be of the same chemical character as R. When molybdenum or other Group VIB metal is employed, the structural formula is represented as shown below:

Suitable beta-diketone The process is effected, as hereinabove set forth, by initially dissolving the desired quantity of the betadiketone complex, such as molybdyl acetylacetonate, in the hydrocarbon charge stock. The resulting mixture is then heated, preferably in a non-reducing atmosphere and particularly in the absence of free hydrogen, at a temperature less than about 310 C. and for a time sufficient to effect the decomposition of the molybdyl acetylacetonate, thereby resulting in a colloidal suspension, or dispersion, of the metallic component within the hydrocarbon charge stock. The presence of free hydrogen during the decomposition of the beta-diketone complex has a tendency to affect detrirnentally the activity of the catalyst with respect to the conversion of the pentaneinsoluble fraction and the removal of the organic metal compounds such as porphyrins. The colloidal dispersion is then passed into a suitable reaction zone at a temperature within the range of from about 225 C. to about 500 C., and under a hydrogen pressure within the range of 500 to about 5000 pounds per square inch gauge. In order to maintain the catalyst in its decomposed form, either as the metal or as a lower oxide thereof, it is neces sary that the reaction zone be maintained substantially completely free from carbon monoxide. The process may be conducted in a batch-type procedure or in an enclosed vessel through which the colloidal suspension is passed either in upward or downward flow. The normally liquid hydrocarbons may be separated from the total reaction zone elfiuent by any suitable means, for example, through the use of a centrifuge, the resulting catalyst sludge being converted back to the beta-diketone complex by any of the well known chemical means. The ammonia and hydorgen sulfide, resulting from the destructive conversion of sulfurous and nitrogenous compounds contained within the petroleum crude oil, are removed, along with any light parafiinic hydrocarbons including methane, ethane and propane, in a gaseous phase.

Although the process of the present invention is conducted in the presence of hydrogen, the decomposition of the beta-diketone complex such as molybdyl acetylacetonate, must be effected in the absence thereof. It is further preferred that the decomposition, to form the colloidal suspension, be conducted in the substantial absence of other Well-known reducing agents. Depending upon the particular beta-diketone complex selected as the catalyst source, the dispersed material will exist in the elemental metal or as a lower oxide form thereof. In any event, it is understood that the stated concentrations are computed on the basis of the elemental metal. The decomposition of the beta-diketone complex is conducted at a temperature less than about 310 C. in order to avoid initial cracking the petroleum crude oil prior to effecting complete decomposition.

The following example is given to illustrate the process of the present invention and the effectiveness thereof in removing nickel and vanadium from a petroleum crude oil, and in converting pentane-insoluble asphaltenes while simultaneously effecting the conversion of sulfurous and nitrogenous compounds into sulfur and nitrogen-free hydrocarbons. It is not intended that the present invention be unduly limited to the catalyst, charge stock, and/or operating conditions employed within the example. Spectrographic emission was employed to analyze the product efiluent for the concentration of metals remaining.

Example The crude oil employed to illustrate the benefits afforded through the utilization of the present invention, was a Wyoming sour crude oil having a gravity of 232 API at 60 F. The crude oil contained 2.8% by weight of sulfur, approximately 2700 ppm. of nitrogen, 18 ppm. of nickel and 71 ppm. of vanadium as metal porphyrins, computed as the elemental metal. In addition, the sour crude consisted of 8.37% by weight of pentane-insoluble asphaltenes. As hereinafter indicated, the process of the,

present invention elfects the conversion of a significant proportion of such asphaltenes, and to the degree that the same no longer exert a detrimental effect upon further processing.

The colloidally dispersed catalysts were prepared by decomposing the indicated beta-diketone complex within the sour crude oil, thereafter subjecting the mixture to conversion in a rotating autoclave maintained at about 400 C., at an imposed hydrogen pressure of about 200 atmospheres. Each of the colloidal suspensions remained in the autoclave at the foregoing conditions for a period of from about 4 to about 8 hours.

Molybdyl acetylacetonate, in an amount of 22.8 grams, was added to 210 grams of Wyoming sour crude, the mixture being heated to a temperature of 220 C. to decompose the molybdyl acetylacetonate. 228 grams of the resulting colloidal suspension were charged into an autoclave, pressured to 100 atmospheres with hydrogen and heated to a temperature of 400 C., thus raising the pressure to about 200 atmospheres; the autoclave was maintained at these conditions for a period of 8 hours. The total product efiluent was centrifuged, the resulting normally liquid hydrocarbons indicating 99 p.p.m. of nitrogen, 0.10% by weight of sulfur, 0.05 p.p.m. of nickel, and less than 0.01 p.p.m. of vanadium. Such a hydrorefined product will indicate less than 0.5% by weight of pentane-insolubles.

33 grams of molybdyl acetylacetonate and 5 grams of nickel acetylacetonate were mixed with 300 grams of the Wyoming sour crude, the mixture being heated at a temperature of 300 C. for a period of 1 hour. 200 grams of the resulting colloidal suspension were charged to the autoclave, pressured to 100 atmospheres with hydrogen and then heated to a temperature of 400 0., thereby increasing the pressure to about 200 atmospheres. These conditions were maintained for a period of 4 hours. The resulting liquid product, after the catalyst sludge had been removed in a centrifuge, indicated less than about 0.01% by weight of sulfur, 51 p.p.m. of nitrogen, 0.1 p.p.m. of nickel and less than 0.5 p.p.m. of vanadium A significant degree of conversion to lower-boiling hydrocarbon products was effected, since the liquid product eflluent indicated a gravity, API, of 31.7.

21.7 grams of molybdyl acetylacetonate and 3.5 grams of nickel acetylacetonate were admixed with 200 grams of the Wyoming sour crude. The total mixture was charged into the rotating autoclave, pressured to 100 atmospheres -Wtih hydrogen and heated to 400 C., raising the pressure to about 200 atmospheres. Through this procedure, the decomposition of the molybdyl and nickel acetylacetonate was effected in situ, in the presence of hydrogen. The foregoing conditions were'maiintained for a period of 4 hours, the final liquid product indicating 1404 p.p.m. of nitrogen as compared to 51 p.p.m. resulting when the decomposition was elfected in the absence of hydrogen. I

The foregoing specification and example clearly illustrate the advantages aiforded the hydroefining of petroleum crude oils through the utilization of the method of the present invention. It is of particular interest to note that the concentrationof nickel and vanadium porphyrins, as well as pentane-tinsoluble asphaltenes, is decreased to a level permitting subsequent utilization of the crude oil, either for further processing or distillation, and further that at least a portion of the crude oil was converted into lower-boiling hydrocarbon products.

I claim as my invention:

1. A process for hydrorefining, hydrocarbon charge stock which comprises admixing said charge stock with at 6 least one beta-diketone complex of a metal selected from the group consisting of molybdenum, tungsten, iron, nickel and cobalt, said compound being decomposable at below about 310 C., heating the resulting mixture in a nonreducing atmosphere at a temperature less than about 310 C. and for a time sufiicient to decompose said betadiketone complex, thereafter adding hydrogen to the resulting colloidal suspension and reacting the mixture thus formed at a temperature in excess of about 225 C. and at a pressure greater than about 500 pounds per square inch gauge, and recovering a hydrorefined liquid product.

2. The process of claim 1 further characterized in that the colloidal suspension of said charge stock and decomposed beta-diketone complex is reacted with hydrogen at a temperature Within the range of from about 225 C. to about 500 C. and under an imposed pressure of from about 500 to about 5000 pounds per square inch gauge.

3. The process of claim 1 further characterized in that said beta-diketone complex comprises molybdyl acetylacetonate.

4. The process of claim 1 further characterized in that said beta-diketone complex comprises molybdyl acetylacetonate and nickel acetylacetonate.

5. A process for hydrorefining a petroleum crude oil containing pentane-insoluble asphaltenes which compirses.

admixing said crude oil with at least one beta-diketone complex of a metal selected from the group consisting of molybdenum, tungsten, iron, nickel and cobalt, said compound being decomposable at below about 310 0., heating the resulting mixture in a non-reducing atmosphere at a temperature less than about 310 C. and for a time suflicient to decompose said beta-diketone complex, thereafter adding hydrogen to to the resulting colloidal suspension and reacting the mixture thus formed at a temperature in excess of about 225 C. and at a. pressure greater than about 500 pounds per square inch gauge, and recovering said crude oil substantially free from pentaneinsoluble asphaltenes.

6. The process of claim 5 further characterized in that the mixture of said crude oil and decomposed betadiketone complex is reacted With hydrogen in the absence of carbon monoxide.

7. The process of claim 6 further characterized in that said beta-diketone complex comprises molybdyl acetylacetonate.

8. A process for hydrorefining a petroleum crude oil containing pentane-insoluble asphaltenes which comprises admixing said crude oil with molybdyl acetaylacetonate, heating the resulting mixture at a temperature less than about 310 C. in a non-reducing atmosphere and for a time sufiicient to decompose said molybdyl acetylacetonate, thereafter adding hydrogen to the resulting colloidal suspension and reacting the mixture thus formed in the absence of carbon monoxide, at a temperature within the range of from about 225C. to about 500 C. and at a pressure of from about 500 to about 5000 pounds per square inch gauge, and recovering said crude oil substantially free from pentane-insoluble asphaltenes.

References Cited by the Examiner UNITED STATES PATENTS 2,781,410 2/57 Ziegler et al 260683.15 2,999,075 9/61 Pruett 252472 3,006,844- 10/ 6 1 Limido et a1 208217 3,050,562 8/62 Klopfer 252431 3,053,756 9/ 62 Nottes et a1 252431 ALPHONSO D. SULLIVAN, Primary Examiner.

PA-UL M. COUGHLAN, 111., Examiner. 

1. A PROCESS FOR HYDROREFINING, HYDROCARBON CHARGE STOCK WHICH COMPRISING ADMIXING SAID CHARGE STOCK WITH AT LEAST ONE BETA-DIKETONE COMPLEX OF A METAL SELECTED FROM THE GROUP CONSISTING OF MOLYBDENUM, TUNGSTEN, IRON, NICKEL AND COBALT, SAID COMPOUND BEING DECOMPOSABLE AT BELOW ABOUT 310*C., HEATING THE RESULTING MIXTURE IN A NONREDUCING ATMOSPHERE AT A TEMPERATURE LESS THAN ABOUT 310*C. AND FOR A TIME SUFFICIENT TO DECOMPOSE SAID BETADIKETONE COMPLEX, THEREAFTER ADDING HYDROGEN TO THE RESULTING COLLOIDAL SUSPENSION AND REACTING THE MIXTURE THUS FORMED AT A TEMPERATURE IN EXCESS OF ABOUT 225*C. AND AT A PRESSURE GREATER THAN ABOUT 500 POUNDS PER SQUARE INCH GAUGE, AND RECOVERING A HYDROREFINED LIQUID PRODUCT. 